Safety drilling and fishing bumper sub



Sept. 18, 1951 D. u. SHAFFER v SAFETY DRILLING AND FISHING BUMPER SUB Filed Jan. 24, 1947 INVENTOR, 2010?; 76 524 :7;

Isl Zn Patented Sept. 18, 1951 UNITED: STATE assazse SAFETY'DRILLING ag FISHING BUMPER Donald U. Shaffer, Bra, Calif. Application January 24, 1947, Serial No. 123,957

2 Claims.

This invention is a safety joint or sub for use .in. deep well tool strings.

In such tool strings a bumper sub is mounted .at a position above the drill or tool stem to transmit rotation thereto and to bump up Or down on the stem as may be desired from time to time during a given job. These subs each include mutually telescopic barrel and mandrel parts and have a packing device to prevent leak of circulation liquid at the sub from the flow bore of the string and sub.

During operation of the tool string the drill cuts down in the formation at the foot of the well hole and the packing assembly of the sub comes into engagement with the drive sleeve in which the mandrel of the sub reciprocates. It frequently happens that this engagement unscrews and loosens the packing assembly and thereat starts a leak from the sub out into the formation hole, and creates a hazard for the tool.

Therefore, an object of the invention is to provide a safety, in the sub, which is a positive guard against such a loosening of the packing assembly and the start of a leak.

The invention has the further object of providing a locking part on the sub mandrel which will take the operating engagement when the drive sleeve arrests further relative descent of the sub mandrel during drilling or when the barrel and the sleeve are pulled up to jolt or bump the drill mandrel; and to provide, by said part, against undesired rotational effort from the drive sleeve to the packing assembly and which effort would tend to loosen the packing.

The invention provides a bumper sub having a mandrel provided with a screwed-on packing assembly and a safety, non-rotative guard part or collar, on the mandrel and between the assembly mentioned and the drive sleeve rotatively connecting the barrel and the mandrel and which collar has the dual function of forming the up-bump anvil for the hammer-effect drive sleeve, and of guarding the packing assembly from objectionable contact by and loosening effort of the sleeve.

The invention consists in certain advancements in bumper subs as set forth in the ensuing disclosure and having, with the above, additional objects and advantages as hereinafter developed, and whose constructions, combinations and subcombintions and details of means will be made manifest in the following description of the herewith illustrative embodiment and its manner of operation; it being understood that modifications, variations and adaptations may be resorted -2 I to within the scope, spirit andprinciples of the invention as it is more directly claimed in conclusion hereof.

- Figure 1 is an axial section and Partial side elevation of the sub unit; the barrel and the mandrel being relatively,slightly extended, for clarity.

Figure 2 is a bottom plan of the guard or collar. The sub structurally includes a substantial, outer barrel 2 having a top-end, string screw box or socket 3, and a bottom-end bushing sleeve 4 screwed into its bore and presenting a bumping shoulder or hammer end 5.

This sleeve has internal, longitudinal feathers 4f reciprocating axially in long splines 6 of a central mandrel 1 working in the bore or chamber of the barrel and being hollow for liquid circulation through string tool sections, not shown. The lower end of the mandrel has provision, as a screw pin 1p, for joining a desired tool string section, as of a drill stem make-up.

For down bumping operations the sleeve 4 is adapted to be banged down onto an abutment shoulder is of the mandrel.

To prevent circulation leak at the working joint between the barrel and the mandrel a packing assembly including a screw band 8 is mounted on the upper end of the mandrel.

If, during operation of the sub (when mounted in a tool string) the screw band and the other parts of the said assembly are worked loose on the mandrel then a leak is set up from the sub unit out into the well hole, with hazard to the tool parts and possible loss of the well hole.

To prevent the direct engagement of the upper end of the drive sleeve 4 with the packing band B ultimately, as the mandrel works to lowest position in the barrel, an intercepting means is provided to engage with and take vibrations from the shoulder 5 of the sleeve l-and thus prevent objectionable engagement of the sleeve with the band 8, which here is screwed onto the mandrel and might be worked loose. This intercepting means is a substantial annular shoulder part united non-rotatively with the mandrel just below the packing assembly band 8. In the present embodiment this shoulder part is a substanial collar 10 concentrically mounted on the mandrel and removably fitting between the mandrel and the barrel and whoselower face is directly engageable by the annular, hammer end 5 of the sleeve 4. The lower face of the collar is jammed down onto the nearby ends of the splines 6 and has a circle of clutch teeth ll meshing endwise into the spaces between the upper ends of the splines 6 to lock the collar to the mandrel ior co-rotation, and the radial width of the teeth being such that they may freely telescope into the upper end of the drive sleeve, at limit of down shift of the mandrel in the barrel. Upward shift of the guard collar is precluded by the adjacent band 8; but the latter will have no unscrewing eflort from the action of 'thezdrive sleeve on the, said locked collar.

A ring member I! of packing is compressed against the band 8 by a gland I3 threaded on the top end of the mandrel.

What is claimed is:

1. A bumper sub having, in combination, relatively telescopic mandrel and barrel parts one of which has longitudinal splines, and ,the other a drive sleeve mutually fitting the splines and slidable on the spiined part, a packing, assembly including a member screwed onto the mandrel ipart. abovethe splines, a "band-screwed ,onto' the .lnandrel and, irictionallyc locking said-member, and means whereby said band is protected against loosening effort by-the sleeve during operation =of: the-sub and including a,=guard collar: :interlocked :with the .said.splines and removably mounted on the mandrel and in seating engageably interlocking to the splines, a band screwed on the mandrel and jamming said member onto said splines, and a packing gland screwed on the mandrel and locking the said band in place on the splines.

DONALD U. SHAFFER.

REFERENCES CITED The following references are of record in the file of this patent:

' UNITED STATES PATENTS Number Name Date 1,686,945 Abercrombie 1iOct. 9, 1928 1,844,257 .Lincoln Febi-B, 1932 2,058,166 McCullough Oct. 20, 1936 2,180,223 Collett Nov. 14, 1939 2,199,969 Hamm May'7,1940 

